Question

When the momentum of a body decreases by 10%. its Kinetic Energy decreases by:

• A. 20%
• B. 40%
• C. 36%
• D. none of these

Answer 1

The correct option is D none of these

$P=mv$ momentum

And $K=\frac{1}{2}m{v}^2$ kinetic energy.

Now $K=\frac{P^2}{2m}$

If P$\to$0.9P

Then K$\to$ ${0.9}^2$=$0.81$

i.e. decreased by 19 percent.

None of the above options is correct.